tire pressure, as stated in the owners manuals of you vehicle and camper are
designed to operate safely at the maximum load.

1) How much does your trialer - fully loaded - weigh and how much are you
putting in your vehicle?

go to a truck scale -  fully loaded and refer to your vehicles manual for a
start...

john

Hi,
You adjust the hitch height to get the trailer level.  The correct
hitch height is when the RV is hooked up to the tow vehicle and the RV
is sitting level front to rear.   If the rear of the tow vehicle is down
and you can't get the trailer level then you may need an equalizer hitch
or new shocks or springs or you are overloaded.

Tires are designed to carry a specific weight at a specific PSI.
Whenever you add weight to the rear you should up the tire pressure to
the max PSI shown on the tire. You should also find out how much weight
you are carrying.  If you are overweight on the rear then you have to
reduce the weight.  There is no way around that.  Otherwise you will
have your headlights pointed skyward and it will feel like you have to
make huge steering inputs to control the vehicle.  It will feel as you
say loose.

Take care and Happy Campin...

Just my personal preference... I keep the trailer tires at just under the max
pressure listed on the tire..

On the truck, I go a little soft until it's time to tow, then go up to almost
max in the rear and a little less in front..

My tire guy says that the trailer tires should be filled to close to max when
cold... too little pressure not only decreases fuel economy and handling but
worst of all produces more tire heat..
Mac

https://home.comcast.net/~mac.davis
https://home.comcast.net/~mac.davis/wood_stuff.htm

I've read a good article on tire pressures, not just related to trailer
towing. The fear is that you overheat your tires. If the temperature of
the tire gets to the point where the rubber and the reinforcing material
begin to separate then you need to fear. The article went on to say that
generally tire manufacturers are looking for no more than 5% from cold
tire temperature increase. The article went on further suggesting that if
you measure the temperature prior to traveling and measure it at periodic
intervals as you travel you can fine tune the pressure based on your
initial temperature check (providing the road temp and so on has not
changed). Of course loading your vehicle no more than what it can handle
was never suggested. Having said all this I have never done this as it
seems a lot of work to get an ideal pressure, but if you are looking for
the "best" pressure to run them at, here you go.